Multi-rate systems have been used in digital signal processing (DSP) and continue to find applications in new and emerging areas. Small area and low power consumption are important criteria in the design of DSP systems. These criteria necessitate efficient implementation of basic building blocks of multi-rate signal processing, namely decimators and interpolators. FIR filters are usually preferred in multi-rate systems over infinite impulse response (IIR) filters because of their inherent stability, easily-designed linear phase response and computational efficiency. Polyphase decomposition of an FIR filter is a power efficient technique as it allows operation of subfilters at lower data rates and also computation of only useful output samples in the case of decimation.
Multiplication is a major source of power dissipation in FIR filters. Techniques have been proposed to achieve low power multipliers. A differential coefficient technique has been proposed to reduce coefficient precision in single rate FIR filters. Notwithstanding these developments, there is a need for improved decimation FIR filters.